Efficacy of insecticides on fruit yield and fruit damage of eggplants (Solanum melongena L.) in Ogbomoso, Oyo State, Nigeria

Abstract

Field trials were conducted during 2016 and 2017 raining seasons at the Teaching and Research Farm, Ladoke Akintola University of  Technology, Ogbomoso, to determine the effects of leaf extracts of Pawpaw, Tobacco and Cashew on insect pests of three selected  eggplant varieties. Synthetic insecticide (Lambdachyalothin) and untreated plants were included in the experiment for comparison and  each treatment was replicated three times. The experiments were laid out in Randomized Complete Block Design. Data were collected on  insect pests, fruit damage and fruit yield. Four major insect pests of eggplant – Zonocerus variegatus, Spodoptera litoralis, Leucinodes  ornabalis and Epilachna species were observed. Among the tested varieties, S. depressum had the least significant (P< 0.05) infestation.  All the tested leaf plant extracts were effective in the control of the observed insect pests when compared with the level of insect pest attack on untreated plants. However, cashew extract had the highest insecticidal efficacy (55%) compared with other tested plant extracts  while insecticidal potential of pawpaw extract was comparable to tobacco extracts. Meanwhile, none of the tested plant leaf  extracts was effective as Lambdachyhalothrin in the control of the observed insect pests. Among the tested varieties, Solanum  depressum had highest fruit yield ( 3.45 - 3.88 t/ha) and least fruit damage.